Electro-optical liquid-crystal display

ABSTRACT

The invention relates to an electro-optical liquid-crystal display having a realignment layer for realigning the liquid crystals whose field has a significant component parallel to the liquid-crystal layer and which contains a liquid-crystalline medium of positive dielectric anisotropy, where the medium comprises at least one mesogenic compound and at least one alkenyl compound of formula I*.

The invention relates to an electro-optical liquid-crystal displayhaving a realignment layer for realigning the liquid crystals whosefield has a significant component parallel to the liquid-crystal layerand which contains a liquid-crystalline medium of positive dielectricanisotropy, where the medium comprises at least one mesogenic compoundcontaining a 3,4,5-trifluorophenyl group and at least one alkenylcompound of the formula I*.

BACKGROUND OF THE INVENTION

In conventional liquid-crystal displays (TN, STN, OMI or AMD-TN), theelectric fields for realignment are generated essentially perpendicularto the liquid-crystal layer.

International Patent Application WO 91/10936 discloses a liquid-crystaldisplay in which the electric signals are generated in such a way thatthe electric fields have a significant component parallel to theliquid-crystal layer (IPS, in-plane switching). The principles ofoperating such a display are described, for example, by R. A. Soref inJournal of Applied Physics, vol. 45, No. 12, pp. 5466-5468 (1974).

EP 0 588 568 discloses various ways of addressing a display of thistype.

These IPS displays can be operated with liquid-crystalline materialseither of positive or of negative dielectric anisotropy (Δε≠0). However,using the materials known hitherto, relatively high threshold voltagesand long response times are reached in IPS displays.

SUMMARY OF THE INVENTION

An object of the invention was therefore to indicate liquid-crystallinematerials which are suitable for achieving relatively low thresholdvoltages and short response times in IPS displays.

Upon further study of the specification and appended claims, furtherobjects and advantages of this invention will become apparent to thoseskilled in the art.

Surprisingly, objects of the invention are achieved by the use ofliquid-crystalline materials comprising at least one compound of theformula I containing a 3,4,5-trifluorophenyl group and at least onecompound of the formula I*, described below.

Such compounds are disclosed, for example, in EP 0 122 389 and in EP 0387 032 and WO 91/03450.

However, there is no indication therein that the threshold voltages andthe response times of IPS displays can be improved with the aid of thesesubstances. The novel IPS mixtures are distinguished at least by theirrelatively high clearing points and low rotational viscosity values.

An aspect of the invention therefore relates to an electro-opticalliquid-crystal display having a realignment layer for realigning theliquid crystals whose field has a significant component parallel to theliquid-crystal layer and which contains a liquid-crystalline medium ofpositive dielectric anisotropy, where the medium comprises at least onecompound of the formula I ##STR1## in which R¹ is H, an alkyl or alkenylradical having 1 to 15 carbon atoms which is unsubstituted,monosubstituted by CN or CF, or at least monosubstituted by halogen,where one or more CH₂ groups in these radicals may also, in each caseindependently of one another, be replaced by --O--, --S--, --CO--,--CO--O--, --O--CO-- or --O--CO--O-- in such a way that O atoms are notlinked directly to one another,

A¹ and A² are each, independently of one another, a

(a) trans-1,4-cyclohexylene radical or 1,4-cyclohexenylene radical, inwhich, in addition, one or more non-adjacent CH₂ groups may be replacedby --O-- and/or --S--,

(b) 1,4-phenylene radical, in which, in addition, one or two CH groupsmay be replaced by N,

(c) radical from the group. consisting of 1,4-bicyclo[2.2.2]octylene,piperidine-1,4-diyl, naphthalene-2,6-diyl,deca-hydronaphthalene-2,6-diyl and1,2,3,4-tetrahydronaphthalene-2,6-diyl,

where the radicals (a) and (b) may be substituted by one or two fluorineatoms,

Z¹ and Z² are each, independently of one another, --CO--O--, --O--CO--,--CH₂ O--, --OCH₂ --, --CH₂ CH₂ --CH═CH--, --C═C--, or a single bond, orone of the radicals Z¹ and Z² is --(CH₂)₄ -- or --CH═CH--CH₂ CH₂ --, and

m is 0, 1 or 2,

and at least one compound of the formula I* ##STR2## in which R^(1*) is1E-alkenyl or 3E-alkenyl having 2-7 carbon atoms,

R^(2*) is F, or an alkyl or alkoxy radical having 1 or 6 carbon atomswhich is unsubstituted or monosubstituted to perfluososubstituted byfluorine, ##STR3## 1 is 0 or 1, and L¹ and L² are each, independently ofone another, H or F.

Preferred embodiments are IPS displays where

the medium additionally comprises at least one compound of the formulaII ##STR4## in which L¹ and L² are each, independently of one another, Hor F.

R² is as defined for R¹,

A³ and A⁴ are each, independently, as defined for A¹ and A²,

Z³ and Z⁴ are each, independently of one another, as defined for Z¹ andZ², and

n is 0, 1 or 2,

the medium additionally comprises at least one compound of the formulaIII

    R.sup.3 --(A.sup.5 --Z.sup.5).sub.o --A.sup.6 --R.sup.4    III

in which

R³ and R⁴ are each, independently of one another, as defined for R¹,

A⁵ and A⁶ are each, independently, as defined for A¹ and A²,

Z⁵ is in each case, independently of the others, as defined for Z¹ andZ², and

o is 1, 2 or 3;

the medium additionally comprises at least one compound of the formulaIV ##STR5## in which R⁵ is as defined for R¹,

A⁷ and A⁸ are each, independently of one another, as defined for A¹ andA²,

Z⁷ and Z⁸ are each, independently of one another, as defined for Z¹ andZ²,

L¹ and L² are each, independently of one another, H or F,

Q is a polyfluoroalkylene radical of the formula

    --(O).sub.q --(CH.sub.2).sub.r --(CF.sub.2).sub.s --

in which

q is 0 or 1

r is 0 or an integer from 1 to 6 and

s is an integer from 1 to 6,

X is H, F or Cl, and

p is 0, 1 or 2.

Preference is furthermore given to an IPS display in which the pixelsare addressed by means of an active matrix.

The invention furthermore relates to a liquid-crystalline medium ofpositive dielectric anisotropy which comprises at least one compound ofthe formula I and at least one compound of the formula I*, in particularwhich comprises

from 10 to 60% by weight, preferably from 30 to 60% by weight, of atleast one compound of the formula I,

from 5 to 40% by weight, preferably from 10 to 25% by weight, of atleast one compound of the formula I*,

from 0 to 40% by weight, preferably from 0 to 25% by weight, of at leastone compound of the formula II,

from 0 to 30% by weight, preferably from 0 to 15% by weight, of at leastone compound of the formula III, and

from 5 to 50% by weight, preferably from 10 to 30% by weight, of acompound of the formula IV.

The novel liquid-crystalline medium preferably comprises:

at least one compound selected from the formulae Ia and/or 1b ##STR6##at least one compound selected from the formulae I*a to I*f ##STR7##where z is 1-12,

R^(*) is H, CH₃, C₂ H₅ or n--C₃ H₇, and

L¹ and L² are each, independently of one another, H or F.

In the compounds I*c to I*f, R² * is preferably a fluorinated alkoxyradical or fluorine, especially OCF₃ or F.

Preferred compounds are compounds of the formulae I*a and 1*c,especially compounds in which R* is H.

Preferred compounds of the formula I*c are selected from the group I*c¹and I*c² ##STR8## at least one compound selected from the formulae IIato IId ##STR9## in a particularly preferred form, at least one compoundof the formula IIa1 ##STR10## at least one compound selected from theformulae IIIa, IIIb and IIIc, ##STR11## and if desired, at least onecompound selected from the formulae IVa and IVb, ##STR12## in which##STR13## and R¹, R², R³, R⁴, R⁵, L¹ and L² are each as defined above.

In a particularly preferred embodiment, the novel media comprise atleast one compound of the formula Ia in which ##STR14## and at least onecompound of the formula I*a and/or I*c.

In a further preferred embodiment, the novel media comprise at least onecompound of the formula Ia and at least one compound of the formula Iband a compound of the formula I*, preferably I*a, and/or I*c.

The novel liquid-crystalline media preferably have a birefringence(Δn)<0.12, particularly preferably from 0.07 to 0.11

The flow viscosity (at 20° C.) of the novel mixtures is preferably lessthan 30 mm².s⁻¹, in particular from 15 to 25 mm².s⁻¹. The specificresistivity of the novel materials at 20° C. is preferably from 5×10¹⁰to 5×10¹³ Ω.cm, particularly preferably from 5×10¹¹ to 5×10¹² Ω.cm.

It has been found that even a relatively small proportion of compoundsof the formulae I* and I in a mixture with conventional liquid-crystalmaterials, but in particular with one or more compounds of the formulaII, III and/or IV, results in a significant lowering of the thresholdvoltage, in favorable levels of rotational viscosity γ, and in fastresponse times, with at the same time broad nematic phases having lowsmectic-nematic transition temperatures being observed.

The compounds of the formulae I*, I to IV are colorless, stable andreadily miscible with one another and with other liquid-crystalmaterials.

The term "alkyl" covers straight-chain and branched alkyl groups having1-7 carbon atoms, in particular the straight-chain groups methyl, ethyl,propyl, butyl, pentyl, hexyl and heptyl. Groups having 2-5 carbon atomsare generally preferred.

The term "alkenyl" covers straight-chain and branched alkenyl groupshaving 2-7 carbon atoms, in particular the straight-chain groups. Inparticular, alkenyl groups are C₂ -C₇ -1E-alkenyl, C₄ -C₇ -3E-alkenyl,C₅ -C₇ -4-alkenyl, C₆ -C₇ -5-alkenyl and C₇ -6-alkenyl, in particular C₂-C₇ -1E-alkenyl, C₄ -C₇ -3E-alkenyl and C₅ -C₇ -4-alkenyl.

Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl,1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl,3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl,4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups having up to 5carbon atoms are generally preferred.

The term "fluoroalkyl" preferably covers straight-chain groups having aterminal fluorine atom, i.e. fluoromethyl, 2-fluoroethyl,3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and7-fluoroheptyl. However, other positions of the fluorine are notexcluded.

The term "oxaalkyl" preferably covers straight-chain radicals of theformula C_(n) H_(2n+1) --O--(CH₂)_(m), in which n and m are each,independently of one another, from 1 to 6. Preferably, n=1 and m is from1 to 6.

Through a suitable choice of the meanings of R¹ to R⁵, the responsetimes, the threshold voltage, the steepness of the transmissioncharacteristic lines, etc., can be modified as desired. For example,1E-alkenyl radicals, 3E-alkenyl radicals, 2E-alkenyloxy radicals and thelike generally result in shorter response times, improved nematictendencies and a higher ratio between the elastic constants k₃₃ (bend)and k₁₁ (splay) compared with alkyl and alkoxy radicals. 4-Alkenylradicals, 3-alkenyl radicals and the like generally result in lowerthreshold voltages and smaller values of k₃₃ /k₁₁ compared with alkyland alkoxy radicals.

A --CH₂ CH₂ -- group in Z¹, Z², Z³, Z⁴, Z⁵, Z⁷ and/or Z⁸ generallyresults in higher values of k₃₃ /k₁₁ compared with a single covalentbond. Higher values of k33/k₁₁ facilitate, for example, flattertransmission characteristic lines in TN cells having a 90° twist (forachieving grey shades) and steeper transmission characteristic lines inSTN, SBE and OMI cells (greater multiplexability), and vice versa.

The optimum mixing ratio between the compounds of the formulae I*, I andII+III+IV depends substantially on the desired properties, on the choiceof the components of the formulae I*, I, II, III and/or IV and on thechoice of any other components present. Suitable mixing ratios withinthe abovementioned range can easily be determined from case to case.

The total amount of compounds of the formulae I*, I to IV in the novelmixtures is not crucial. The mixtures preferably comprise 50-90% byweight of compounds of the formulae I, I* and IV. The mixtures may alsocontain one or more further components in order to optimize variousproperties. However, the observed effect on the response times and thethreshold voltage is generally higher the greater the totalconcentration of compounds of the formulae I*, I and IV.

In a particularly preferred embodiment, the novel media comprisecompounds of the formula IV in which Q--X is OCF₃ or OCHF₂. A favorablesynergistic effect with the compounds of the formula I*, I and IIresults in particularly advantageous properties.

The novel liquid-crystalline media preferably comprise 2 to 40, inparticular 4 to 30, components as further constituents besides one ormore compounds of the formulae I*, I, II, III and IV. These media veryparticularly preferably comprise 7 to 25 components besides one or morecompounds according to the invention. These further constituents arepreferably selected from nematic or nematogenic (monotropic orisotropic) substances, in particular substances from the classes of theazoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl orcyclohexyl benzoates, phenyl or cyclohexyl esters ofcyclohexanecarboxylic acid, phenyl or cyclohexyl esters ofcyclohexylbenzoic acid, phenyl or cyclohexyl esters ofcyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl esters of benzoicacid, of cyclohexanecarboxylic acid and ofcyclohexylcyclohexanecarboxylic acid, phenylcyclohexanes,cyclohexylbiphenyls, phenylcyclohexylcyclohexanes,cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes,1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- orcyclohexylpyrimidines, phenyl- or cyclo-hexylpyridines, phenyl- orcyclohexyldioxanes, phenyl- or cyclohexyl-1,3-dithianes,1,2-diphenylethanes, 1,2-di-cyclohexylethanes,1-phenyl-2-cyclohexylethanes,1-cyclohexyl-2-(4-phenylcyclohexyl)ethanes,1-cyclohexyl-2-biphenylylethanes, 1-phenyl-2-cyclohexylphenylethanes,optionally halogenated stilbenes, benzyl phenyl ethers, tolans andsubstituted cinnamic acids. The 1,4-phenylene groups in these compoundsmay also be fluorinated.

The most important compounds suitable as further constituents of novelmedia can be characterized by the formulae 1, 2, 3, 4 and 5:

    R'--L--E--R"                                               1

    R'--L--COO--E--R"                                          2

    R'--L--OOC--E--R"                                          3

    R'--L--CH.sub.2 CH.sub.2 --E--R"                           4

    R'--L--C.tbd.C--E--R"                                      5

In the formulae 1, 2, 3, 4 and 5, L and E, which may be identical ordifferent, are in each case, independently of one another, a bivalentradical from the group formed by --Phe--, --Cyc--, --Phe--Phe--,--Phe--Cyc--, --Cyc--Cyc--, --Pyr--, --Dio--, --G--Phe-- and --G--Cyc--and their mirror images, where Phe is unsubstituted orfluorine-substituted 1,4-phenylene, Cyc is trans-1,4-cyclohexylene or1,4-cyclo-hexenylene, Pyr is pyrimidine-2,5-diyl or pyridine-2,5-diyl,Dio is 1,3-dioxane-2,5-diyl and G is 2-(trans-1,4-cyclohexyl)ethyl,pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E ispreferably Cyc, Phe or Phe-Cyc. The novel media preferably comprise oneor more components selected from the compounds of the formulae 1, 2, 3,4 and 5 in which L and E are selected from the group consisting of Cyc,Phe and Pyr and simultaneously one or more components selected from thecompounds of the formulae 1, 2, 3, 4 and 5 in which one of the radicalsL and E is selected from the group consisting of Cyc, Phe and Pyr andthe other radical is selected from the group consisting of --Phe--Phe--,--Phe--Cyc--, --Cyc--Cyc--, --G--Phe-- and --G--Cyc--, and optionallyone or more components selected from the compounds of the formulae 1, 2,3, 4 and 5 in which the radicals L and E are selected from the groupconsisting of --Phe--Cyc--, --Cyc--Cyc--, --G--Phe-- and --G--Cyc--.

In a smaller sub-group of the compounds of the formulae 1, 2, 3, 4 and5, R' and R" are in each case, independently of one another, alkyl,alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy having up to 8carbon atoms. This smaller sub-group is henceforth called group A, andthe compounds are labelled with the sub-formulae 1a, 2a, 3a, 4a and 5a.In most of these compounds, R' and R" are different from one another,one of these radicals usually being alkyl, alkenyl, alkoxy oralkoxyalkyl.

In another smaller sub-group of the compounds of the formulae 1, 2, 3, 4and 5 which is known as group B, R" is --F, --Cl, --NCS or --(O)_(i)CH₃₋(k+l) F_(k) Cl_(l), where i is 0 or 1, and k+l is 1, 2 or 3; thecompounds in which R" has this meaning are labelled with thesub-formulae 1b, 2b, 3b, 4b and 5b. Particular preference is given tothose compounds of the sub-formulae 1b, 2b, 3b, 4b and 5b in which R" is--F, --Cl, --NCS, --CF₃, --OCHF₂ or --OCF₃.

In the compounds of the sub-formulae 1b, 2b, 3b, 4b and 5b, R' is asdefined for the compounds of the sub-formulae 1a-5a and is preferablyalkyl, alkenyl, alkoxy or alkoxyalkyl.

In a further smaller sub-group of the compounds of the formulae 1, 2, 3,4 and 5, R" is --CN; this sub-group is known henceforth as group C, andthe compounds of this sub-group are correspondingly described bysub-formulae 1c, 2c, 3c, 4c and 5c. In the compounds of the sub-formulae1c, 2c, 3c, 4c and 5c, R' is as defined for the compounds of thesub-formulae 1a-5a and is preferably alkyl, alkoxy or alkenyl.

In addition to the preferred compounds of groups A, B and C, othercompounds of the formulae 1, 2, 3, 4 and 5 having other variants of theproposed substituents are also customary. All these substances can beobtained by methods which are known from the literature or analogouslythereto.

Besides the compounds of the formulae I and I*, the novel mediapreferably comprise one or more compounds selected from group A and/orgroup B and/or group C. The proportions by weight of the compounds fromthese groups in the novel media are preferably

Group A: 0 to 90%, preferably 20 to 90%, in particular 30 to 90%

Group B: 0 to 80%, preferably 10 to 80%, in particular 10 to 65%

Group C: 0 to 80%, preferably 5 to 80%, in particular 5 to 50%,

the sum of the proportions by weight of the group A and/or B and/or Ccompounds present in the particular novel media preferably being 5% to90% and in particular 10% to 90%.

The novel media preferably comprise 1 to 40%, particularly preferably 5to 30%, of compounds of the formulae I and I*. Further preferred mediaare those which comprise more than 40%, in particular 45 to 90%, ofcompounds of the formulae I and I*. The media preferably comprise three,four or five compounds of the formulae I and I*.

The structure of the IPS display according to the invention correspondsto the usual construction for such displays, as described, for example,in WO 91/10936 or EP 0 588 568. The term conventional construction isbroadly drawn here and also covers all derivatives and modifications ofthe IPS display, in particular, for example, including matrix displayelements based on poly-Si TFT or MIM.

However, an essential difference between the displays according to theinvention and those conventional hitherto is in the choice of theliquid-crystal parameters of the liquid-crystal layer.

The liquid-crystal mixtures which can be used in accordance with theinvention are prepared in a manner conventional per se. In general, thedesired amount of the components used in lesser amount is dissolved inthe components making up the principal constituent, expediently atelevated temperature. It is also possible to mix solutions of thecomponents in an organic solvent, for example in acetone, chloroform ormethanol, and, after mixing, to remove the solvent again, for example bydistillation.

The dielectrics may also comprise further additives known to the personskilled in the art and described in the literature. For example, 0-15%of pleochroic dyes or chiral dopants can be added.

C denotes a crystalline phase, S a smectic phase, S_(B) a smectic Bphase, N a nematic phase and I the isotropic phase.

V_(o) denotes the capacitive threshold voltage. An denotes the opticalanisotropy and n_(o) the ordinary refractive index (in each case at 589nm). Δε denotes the dielectric anisotropy (Δε=ε.sub.| -ε.sub.⊥, whereε.sub.| denotes the dielectric constant parallel to the longitudinalaxes of the molecules and ε.sub.⊥ denotes the dielectric constantperpendicular thereto). The electro-optical data were measured in aplanar cell at 20° C., unless expressly stated otherwise. The opticaldata were measured at 20° C., unless expressly stated otherwise.

In the foregoing and in the following examples, all temperatures are setforth uncorrected in degrees Celsius; and, unless otherwise indicated,all parts and percentages are by weight.

The entire disclosure of all applications, patents and publications,cited above and below, and of corresponding German application No. 19650 372.8, filed Dec. 5, 1996 1996 is hereby incorporated by reference.

In the present application and in the examples below, the structures ofthe liquid-crystal compounds are indicated by acronyms, thetransformation into chemical formulae taking place as in Tables A and Bbelow. All the radicals C_(n) H_(2n+1) are straight-chain alkyl radicalscontaining n or m carbon atoms, respectively. The coding in Table B isself-evident. In Table A, only the acronym for the parent structure isgiven. In individual cases, the acronym for the parent structure isfollowed, separated by a hyphen, by a code for the substituents R¹, R²,L¹ and L² :

    ______________________________________                                        Code for R.sup.1,                                                             R.sup.2, L.sup.1, L.sup.2                                                             R.sup.1          R.sup.2    L.sup.1                                                                           L.sup.2                               ______________________________________                                        nm      C.sub.n H.sub.2n+1                                                                             C.sub.m H.sub.2m+1                                                                       H   H                                     nOm     C.sub.n H.sub.2n+1                                                                             OC.sub.m H.sub.2m+1                                                                      H   H                                     nO.m    OC.sub.n H.sub.2n+1                                                                            C.sub.m H.sub.2m+1                                                                       H   H                                     n       C.sub.n H.sub.2n+1                                                                             CN         H   H                                     nN.F    C.sub.n H.sub.2n+1                                                                             CN         F   H                                     nN.F.F  C.sub.n H.sub.2n+1                                                                             CN         F   F                                     nF      C.sub.n H.sub.2n+1                                                                             F          H   H                                     nOF     OC.sub.n H.sub.2n+1                                                                            F          H   H                                     nCl     C.sub.n H.sub.2n+1                                                                             Cl         H   H                                     nF.F    C.sub.n H.sub.2n+1                                                                             F          F   H                                     nCF.sub.3                                                                             C.sub.n H.sub.2n+1                                                                             CF.sub.3   H   H                                     nOCF.sub.3                                                                            C.sub.n H.sub.2n+1                                                                             OCF.sub.3  H   H                                     nOCF.sub.2                                                                            C.sub.n H.sub.2n+1                                                                             OCHF.sub.2 H   H                                     nS      C.sub.n H.sub.2n+1                                                                             NCS        H   H                                     rVsN    C.sub.r H.sub.2n+1 --CH═CH--C.sub.s H.sub.2s --                                            CN         H   H                                     rEsN    C.sub.r H.sub.2n+1 --O--C.sub.2 H.sub.2s--                                                     CN         H   H                                     nAm     C.sub.n H.sub.2n+1                                                                             COOC.sub.m H.sub.2m+1                                                                    H   H                                     nF.F.F  C.sub.n H.sub.2n+1                                                                             F          F   F                                     nCl.F.F C.sub.n H.sub.2n+1                                                                             Cl         F   F                                     nCF.sub.3.F.F                                                                         C.sub.n H.sub.2n+1                                                                             CF.sub.3   F   F                                     nOCF.sub.3.F.F                                                                        C.sub.n H.sub.2n+1                                                                             OCF.sub.3  F   F                                     nOCF.sub.2.F.F                                                                        C.sub.n H.sub.2n+1                                                                             OCHF.sub.2 F   F                                     nOCF.sub.3.F                                                                          C.sub.n H.sub.2n+1                                                                             OCF.sub.3  F   H                                     ______________________________________                                    

Preferred media comprise, in particular, one or more compounds fromTables A and B in addition to the compounds of the formulae I and I*.

                  TABLE A                                                         ______________________________________                                         ##STR15##                                                                    BCH                                                                            ##STR16##                                                                    CCH                                                                            ##STR17##                                                                    CCP                                                                            ##STR18##                                                                    CP                                                                             ##STR19##                                                                    PTP                                                                            ##STR20##                                                                    ECCP                                                                           ##STR21##                                                                    HP                                                                             ##STR22##                                                                    ME                                                                             ##STR23##                                                                    PCH                                                                            ##STR24##                                                                    CH                                                                             ##STR25##                                                                    PDX                                                                            ##STR26##                                                                    K3n                                                                           ______________________________________                                    

                  TABLE B                                                         ______________________________________                                         ##STR27##                                                                    CCP-n.F.F.F                                                                    ##STR28##                                                                    BCH-n.F.F.F                                                                    ##STR29##                                                                    CCZU-n-F                                                                       ##STR30##                                                                    CDU-n-F                                                                        ##STR31##                                                                    CGU-n-F                                                                        ##STR32##                                                                    CC-n-V                                                                         ##STR33##                                                                    CC-n-2V                                                                        ##STR34##                                                                    CCG-V-F                                                                       ______________________________________                                    

EXAMPLE 1

    ______________________________________                                        clearing point       +77° C.                                           .increment.n [589 nm, 20° C.]                                                                0.0763                                                  n.sub.0               1.4735                                                  .increment.ε (1kHz, 20° C.)                                                          +7.8                                                    ε⊥       3.6                                                     rotational viscosity (20° C.)                                                               86 mPa · s                                      V.sub.0               1.19 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.0                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.6                                                     K.sub.3 /K.sub.1      1.36                                                    ______________________________________                                    

    ______________________________________                                               CCP-20CF.sub.3     9.0%                                                       CCP-30CF.sub.3     7.0%                                                       CCP-40CF.sub.3     6.0%                                                       CCP-2F.F.F        10.0%                                                       CCP-3F.F.F        10.0%                                                       CCP-5F.F.F         4.0%                                                       CGU-2-F           10.0%                                                       CGU-3-F            2.0%                                                       CCZU-2-F           7.0%                                                       CCZU-3-F          13.0%                                                       CC-5-V            20.0%                                                       PCH-7F             2.0%                                                ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 2

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +74° C.                                           .increment.n [589 nm, 20° C.]                                                                0.0831                                                  n.sub.0               1.4813                                                  .increment.ε (1kHz, 20° C.)                                                          +6.3                                                    ε⊥       3.6                                                     rotational viscosity (20° C.)                                                               75 mPa · s                                      V.sub.0               1.31 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.7                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.0                                                     K.sub.3 /K.sub.1      1.35                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CC-5-V  17.0%                                                                 PCH-301 8.0%                                                                  CCP-20CF.sub.3                                                                        6.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  BCH-2F.F                                                                              6.0%                                                                  BCH-3F.F                                                                              3.0%                                                                  BCH-2F.F.F                                                                            9.0%                                                                  CCP-2F.F.F                                                                            8.0%                                                                  CCP-3F.F.F                                                                            9.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              8.0%                                                                  CCG-V-F 8.0%                                                           ______________________________________                                    

and has a high contrast and-short response times.

EXAMPLE 3

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +81° C.                                           .increment.n [589 nm, 20° C.]                                                                0.0758                                                  n.sub.0               1.4725                                                  .increment.ε (1kHz, 20° C.)                                                         +10.2                                                    ε⊥       4.3                                                     rotational viscosity (20° C.)                                                               103 mPa · s                                     V.sub.0               1.05 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.1                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             18.1                                                     K.sub.3 /K.sub.1      1.80                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            7.0%                                                                  CCP-3F.F.F                                                                            9.0%                                                                  CCP-5F.F.F                                                                            5.2%                                                                  CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        5.0%                                                                  CCP-40CF.sub.3                                                                        3.0%                                                                  CCP-50CF.sub.3                                                                        5.8%                                                                  PDX-3   1.4%                                                                  PDX-4   7.0%                                                                  PDX-5   6.6%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              13.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  CC-5-V  9.0%                                                                  CC-3-2V 9.0%                                                           ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 4

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +69° C.                                           .increment.n [589 nm, 20° C.]                                                                0.0915                                                  n.sub.0               1.4785                                                  .increment.ε (1kHz, 20° C.)                                                         +12.2                                                    ε⊥       5.0                                                     rotational viscosity (20° C.)                                                               103 mPa · s                                     V.sub.0               0.81 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              7.3                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             15.6                                                     K.sub.3 /K.sub.1      2.14                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                            8.0%                                                                  CCP-5F.F.F                                                                            5.0%                                                                  CCP-20CF.sub.3                                                                        5.0%                                                                  CCP-30CF.sub.3                                                                        9.0%                                                                  CCP-40CF.sub.3                                                                        5.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  PCH-2N.F.F                                                                            2.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  PCH-5N.F.F                                                                            3.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              13.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  PCH-2   5.0%                                                                  PCH-3   9.0%                                                                  CC-5-V  6.0%                                                                  K9      6.0%                                                           ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 5

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +73° C.                                           .increment.n [589 nm, 20° C.]                                                                0.1028                                                  n.sub.0               1.4845                                                  .increment.ε (1kHz, 20° C.)                                                         +11.9                                                    ε⊥       4.6                                                     rotational viscosity (20° C.)                                                               112 mPa · s                                     V.sub.0               0.88 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              8.2                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             16.7                                                     K.sub.3 /K.sub.1      2.05                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCP-20CF.sub.3                                                                        6.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              13.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  K6      8.0%                                                                  K9      7.0%                                                                  CC-5-V  5.0%                                                                  PCH-3   10.0%                                                          ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 6

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +66° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0990                                                 n.sub.0               1.4824                                                  .increment.ε (1kHz, 20° C.)                                                         +12.8                                                    ε⊥       5.2                                                     rotational viscosity (20° C.)                                                               107 mPa · s                                     V.sub.0               0.78 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              7.0                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             15.4                                                     K.sub.3 /K.sub.1      2.19                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                            8.0%                                                                  CCP-5F.F.F                                                                            6.0%                                                                  CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        9.0%                                                                  CCP-40CF.sub.3                                                                        5.0%                                                                  CCP-50CF.sub.3                                                                        4.0%                                                                  PCH-2N.F.F                                                                            2.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  PCH-5N.F.F                                                                            2.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  PCH-2   3.0%                                                                  PCH-3   11.0%                                                                 CC-5-V  3.0%                                                                  K6      3.0%                                                                  K9      8.0%                                                           ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 7

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +69°0 C.                                          .increment.n [589 nm, 20° C.]                                                                +0.0887                                                 n.sub.0               1.4796                                                  .increment.ε (1kHz, 20° C.)                                                         +10.1                                                    ε⊥       4.6                                                     rotational viscosity (20° C.)                                                               82 mPa · s                                      V.sub.0               0.94 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              8.0                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.2                                                     K.sub.3 /K.sub.1      1.65                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            9.0%                                                                  CCP-3F.F.F                                                                            4.0%                                                                  CCP-20CF.sub.3                                                                        6.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-40CF.sub.3                                                                        5.0%                                                                  CCP-50CF.sub.3                                                                        5.0%                                                                  PCH-2N.F.F                                                                            5.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              13.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  CC-5-V  15.0%                                                                 BCH-2F.F                                                                              6.0%                                                                  K6      5.0%                                                                  PTP-201 3.0%                                                           ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 8

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +66° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0986                                                 n.sub.0               1.4816                                                  .increment.ε (1kHz, 20° C.)                                                         +11.8                                                    ε⊥       5.1                                                     rotational viscosity (20° C.)                                                               87 mPa · s                                      V.sub.0               0.84 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              7.5                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.2                                                     K.sub.3 /K.sub.1      1.90                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                             6.0%                                                                 CCP-20CF.sub.3                                                                         7.0%                                                                 CCP-30CF.sub.3                                                                         9.0%                                                                 CCP-40CF.sub.3                                                                         5.0%                                                                 CCP-50CF.sub.3                                                                         4.0%                                                                 PCH-2N.F.F.                                                                            2.0%                                                                 PCH-3N.F.F                                                                             5.0%                                                                 PCH-5N.F.F                                                                             6.0%                                                                 CCZU-2-F 6.0%                                                                 CCZU-3-F 12.0%                                                                CCZU-5-F 6.0%                                                                 PCH-3    9.0%                                                                 CC-5-V   10.0%                                                                PTP-201  4.0%                                                                 K6       7.0%                                                                 BCH-2F.F 2.0%                                                          ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 9

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +70° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0991                                                 n.sub.0               1.4832                                                  .increment.ε (1kHz, 20° C.)                                                         +10.7                                                    ε⊥       4.6                                                     rotational viscosity (20° C.)                                                               83 mPa · s                                      V.sub.0               0.94 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              8.5                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.8                                                     K.sub.3 /K.sub.1      1.62                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                            9.0%                                                                  CCP-5F.F.F                                                                            7.0%                                                                  CCP-20CF.sub.3                                                                        6.0%                                                                  CCP-30CF.sub.3                                                                        7.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  PCH-2N.F.F                                                                            5.0%                                                                  PCH-3N.F.F                                                                            3.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              13.00%                                                                CCZU-5-F                                                                              6.0%                                                                  CC-5-V  15.00%                                                                PTP-201 5.0%                                                                  K6      6.0%                                                                  K9      5.0%                                                           ______________________________________                                    

and has a high contrast and short response times.

EXAMPLE 10

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +77° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0753                                                 n.sub.0               1.4737                                                  .increment.ε (1kHz, 20° C.)                                                          +8.4                                                    ε⊥       3.7                                                     rotational viscosity (20° C.)                                                               122 mPa · s                                     V.sub.0               1.17 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.4                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.7                                                     K.sub.3 /K.sub.1      1.32                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-20CF.sub.3                                                                        5.0%                                                                  CCP-30CF.sub.3                                                                        7.0%                                                                  CCP-40CF.sub.3                                                                        4.0%                                                                  CCP-50CF.sub.3                                                                        5.0%                                                                  CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            9.0%                                                                  CCP-5F.F.F                                                                            7.0%                                                                  CGU-2-F 4.0%                                                                  CGU-3-F 4.0%                                                                  CGU-5-F 4.0%                                                                  CCZU-2-F                                                                              5.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              5.0%                                                                  PCH-7F  8.0%                                                                  CCH-34  6.0%                                                                  CC-5-V  5.0%                                                           ______________________________________                                    

EXAMPLE 11

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +76° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0766                                                 n.sub.0               1.4712                                                  .increment.ε (1kHz, 20° C.)                                                          +8.2                                                    ε⊥       3.8                                                     rotational viscosity (20° C.)                                                               118 mPa · s                                     V.sub.0               1.17 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.0                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.5                                                     K.sub.3 /K.sub.1      1.34                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-20CF.sub.3                                                                         5.0%                                                                 CCP-30CF.sub.3                                                                         7.0%                                                                 CCP-40CF.sub.3                                                                         4.0%                                                                 CCP-50CF.sub.3                                                                         5.0%                                                                 CCP-2F.F.F                                                                             10.0%                                                                CCP-3F.F.F                                                                             9.0%                                                                 CGU-2-F  4.0%                                                                 CGU-3-F  4.0%                                                                 CGU-5-F  4.0%                                                                 CCZU-2-F 5.0%                                                                 CCZU-3-F 12.0%                                                                CCZU-5-F 5.0%                                                                 PCH-7F   8.0%                                                                 CCH-34   6.0%                                                                 CC-5-V   5.0%                                                                 CCP-20CF.sub.3.F                                                                       7.0%                                                          ______________________________________                                    

EXAMPLE 12

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +80° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0835                                                 n.sub.0               1.4775                                                  .increment.ε (1kHz, 20° C.)                                                          +8.0                                                    ε⊥       3.6                                                     rotational viscosity (20° C.)                                                               122 mPa · s                                     V.sub.0               1.15 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.5                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             12.9                                                     K.sub.3 /K.sub.1      1.36                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCH-34  6.0%                                                                  CC-5-V  6.0%                                                                  CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  CGU-2-F 9.0%                                                                  CGU-3-F 7.0%                                                                  CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCG-V-F 6.0%                                                                  CCZU-2-F                                                                              7.0%                                                           ______________________________________                                    

EXAMPLE 13

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +68° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0821                                                 n.sub.0               1.4749                                                  .increment.ε (1kHz, 20° C.)                                                         +11.7                                                    ε⊥       5.0                                                     rotational viscosity (20° C.)                                                               112 mPa · s                                     V.sub.0               0.82 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              7.1                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             15.0                                                     K.sub.3 /K.sub.1      2.11                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                            7.0%                                                                  CCP-5F.F.F                                                                            6.0%                                                                  CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        9.0%                                                                  CCP-40CF.sub.3                                                                        5.0%                                                                  CCP-50CF.sub.3                                                                        4.0%                                                                  PCH-2N.F.F                                                                            2.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  PCH-5N.F.F                                                                            6.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  PCH-2   7.0%                                                                  PCH-3   9.0%                                                                  CC-5-V  9.0%                                                           ______________________________________                                    

EXAMPLE 14

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +82° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0825                                                 n.sub.0               1.4795                                                  .increment.ε (1kHz, 20° C.)                                                          +7.2                                                    ε⊥       3.6                                                     rotational viscosity (20° C.)                                                               109 mPa · s                                     V.sub.0               1.23 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.8                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.6                                                     K.sub.3 /K.sub.1      1.48                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CC-5-V  15.0%                                                                 CCP-20CF.sub.3                                                                        8.0%                                                                  CCP-30CF.sub.3                                                                        7.0%                                                                  CCP-40CF.sub.3                                                                        3.0%                                                                  BCH-2F.F                                                                              8.0%                                                                  BCH-2F.F.F                                                                            7.0%                                                                  CCP-2F.F.F                                                                            11.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            4.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              7.0%                                                                  CCG-V-F 13.0%                                                          ______________________________________                                    

EXAMPLE 15

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +78° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0835                                                 n.sub.0               1.4764                                                  .increment.ε (1kHz, 20° C.)                                                          +8.8                                                    ε⊥       3.9                                                     rotational viscosity (20° C.)                                                               121 mPa · s                                     V.sub.0               1.11 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.7                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.6                                                     K.sub.3 /K.sub.1      1.40                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CC-5-V  12.0%                                                                 CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  CGU-2-F 10.0%                                                                 CGU-3-F 10.0%                                                                 CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCG-V-F 7.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              3.0%                                                           ______________________________________                                    

EXAMPLE 16

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +79° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0763                                                 n.sub.0               1.4745                                                  .increment.ε (1kHz, 20° C.)                                                          +7.9                                                    ε⊥       3.7                                                     rotational viscosity (20° C.)                                                               104 mPa · s                                     V.sub.0               1.19 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.0                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.8                                                     K.sub.3 /K.sub.1      1.38                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        4.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            10.0%                                                                 CCP-5F.F.F                                                                            4.0%                                                                  CGU-2-F 10.0%                                                                 CGU-3-F 2.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              13.0%                                                                 CC-5-V  20.0%                                                                 CCG-V-F 5.0%                                                           ______________________________________                                    

EXAMPLE 17

An IPS display comprises a nematic mixture having

    ______________________________________                                               CC-5-V  11.0%                                                                 CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        6.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  CGU-2-F 10.0%                                                                 CGU-3-F 10.0%                                                                 CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCG-V-F 5.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              3.0%                                                                  PTP-201 3.0%                                                           ______________________________________                                    

and comprising

    ______________________________________                                        clearing point       +78° C.                                           .increment.n [589 nm, 20° C.]                                                                +0.0891                                                 n.sub.0               1.4779                                                  .increment.ε (1kHz, 20° C.)                                                          +8.6                                                    ε⊥       3.9                                                     rotational viscosity (20° C.)                                                               --                                                       V.sub.0               1.13 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.8                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             12.9                                                     K.sub.3 /K.sub.1      1.31                                                    ______________________________________                                    

EXAMPLE 18

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +78.5° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0984                                                 n.sub.0               1.4811                                                  .increment.ε (1kHz, 20° C.)                                                          +8.7                                                    ε⊥       3.9                                                     rotational viscosity (20° C.)                                                               --                                                       V.sub.0               1.14 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                             10.1                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             12.6                                                     K.sub.3 /K.sub.1      1.25                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CC-5-V  7.0%                                                                  CCP-20CF.sub.3                                                                        7.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        6.0%                                                                  CCP-50CF.sub.3                                                                        4.0%                                                                  CGU-2-F 10.0%                                                                 CGU-3-F 10.0%                                                                 CCP-2F.F.F                                                                            10.0%                                                                 CCP-3F.F.F                                                                            11.0%                                                                 CCP-5F.F.F                                                                            3.0%                                                                  CCG-V-F 8.0%                                                                  CCZU-2-F                                                                              7.0%                                                                  CCZU-3-F                                                                              3.0%                                                                  PTP-201 3.0%                                                                  PTP-102 3.0%                                                           ______________________________________                                    

EXAMPLE 19

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +71.5° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0773                                                 n.sub.0               1.4735                                                  .increment.ε (1kHz, 20° C.)                                                         +10.8                                                    ε⊥       4 .4                                                    rotational viscosity (20° C.)                                                               119 mPa · s                                     V.sub.0               0.97 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.2                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.7                                                     K.sub.3 /K.sub.1      1.50                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            9.0%                                                                  CCP-3F.F.F                                                                            7.0%                                                                  CCP-5F.F.F                                                                            6.0%                                                                  CCP-20CF.sub.3                                                                        4.0%                                                                  CCP-30CF.sub.3                                                                        3.0%                                                                  CCP-40CF.sub.3                                                                        3.0%                                                                  CCP-50CF.sub.3                                                                        4.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  PCH-5N.F.F                                                                            6.0%                                                                  CCH-34  5.0%                                                                  CCH-35  4.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  PCH-5   13.0%                                                                 CC-5-V  7.0%                                                           ______________________________________                                    

EXAMPLE 20

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +75.5° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0744                                                 n.sub.0               1.4717                                                  .increment.ε (1kHz, 20° C.)                                                         +10.1                                                    ε⊥       4.3                                                     rotational viscosity (20° C.)                                                               106 mPa · s                                     V.sub.0               1.04 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.8                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             13.2                                                     K.sub.3 /K.sub.1      1.34                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            8.0%                                                                  CCP-3F.F.F                                                                            10.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        3.0%                                                                  CCP-50CF.sub.3                                                                        3.0%                                                                  PCH-2N.F.F                                                                            3.0%                                                                  PCH-3N.F.F                                                                            3.0%                                                                  PCH-5N.F.F                                                                            8.0%                                                                  CCZU-2-F                                                                              5.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              5.0%                                                                  CC-5-V  18.0%                                                          ______________________________________                                    

EXAMPLE 21

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +72.0° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0956                                                 n.sub.0               1.4794                                                  .increment.ε (1kHz, 20° C.)                                                         +11.2                                                    ε⊥       4.8                                                     rotational viscosity (20° C.)                                                               102 mPa · s                                     V.sub.0               0.95 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              8.9                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.8                                                     K.sub.3 /K.sub.1      1.66                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-3F.F.F                                                                            6.0%                                                                  CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        5.0%                                                                  CCP-50CF.sub.3                                                                        6.0%                                                                  PCH-3N.F.F                                                                            11.0%                                                                 CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              6.0%                                                                  PCH-3   11.0%                                                                 CC-5-V  12.0%                                                                 PTP-201 4.0%                                                                  K6      4.0%                                                           ______________________________________                                    

EXAMPLE 22

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +76.5° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0748                                                 n.sub.0               1.4718                                                  .increment.ε (1kHz, 20° C.)                                                         +10.3                                                    ε⊥       4.2                                                     rotational viscosity (20° C.)                                                               109 mPa · s                                     V.sub.0               1.03 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.9                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.7                                                     K.sub.3 /K.sub.1      1.5                                                     ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            8.0%                                                                  CCP-3F.F.F                                                                            10.0%                                                                 CCP-5F.F.F                                                                            5.0%                                                                  CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        3.0%                                                                  CCP-50CF.sub.3                                                                        3.0%                                                                  PCH-3N.F.F                                                                            5.0%                                                                  PCH-5N.F.F                                                                            9.0%                                                                  CCZU-2-F                                                                              5.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              5.0%                                                                  CC-5-V  18.0%                                                          ______________________________________                                    

EXAMPLE 23

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +71.0° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0950                                                 n.sub.0               1.4824                                                  .increment.ε (1kHz, 20° C.)                                                         +10.0                                                    ε⊥       4.5                                                     rotational viscosity (20° C.)                                                               102 mPa · s                                     V.sub.0               0.99 V (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              8.8                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.6                                                     K.sub.3 /K.sub.1      1.67                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        2.0%                                                                  CCP-50CF.sub.3                                                                        3.0%                                                                  PCH-3N.F.F                                                                            10.0%                                                                 CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 PCH-3   14.0%                                                                 CC-5-V  15.0%                                                                 BCH-2F.F                                                                              7.0%                                                                  BCH-3F.F                                                                              6.0%                                                                  BCH-5F.F                                                                              5.0%                                                                  BCH-32  3.0%                                                           ______________________________________                                    

EXAMPLE 24

An IPS display comprises a nematic mixture having

    ______________________________________                                        clearing point       +72.5° C.                                         .increment.n [589 nm, 20° C]                                                                 +0.0850                                                 n.sub.0               1.4771                                                  .increment.ε (1kHz, 20° C.)                                                         +10.3                                                    ε⊥       4.4                                                     rotational viscosity (20° C.)                                                               104 mPa · s                                     V.sub.0               1.00 v (cap.)                                           K.sub.1 [10.sup.-12 N] (20° C.)                                                              9.2                                                     K.sub.3 [10.sup.-12 N] (20° C.)                                                             14.6                                                     K.sub.3 /K.sub.1      1.60                                                    ______________________________________                                    

and comprising

    ______________________________________                                               CCP-2F.F.F                                                                            5.0%                                                                  CCP-3F.F.F                                                                            4.0%                                                                  CCP-5F.F.F                                                                            3.0%                                                                  CCP-20CF.sub.3                                                                        9.0%                                                                  CCP-30CF.sub.3                                                                        8.0%                                                                  CCP-40CF.sub.3                                                                        2.0%                                                                  CCP-50CF.sub.3                                                                        3.0%                                                                  PCH-3N.F.F                                                                            8.0%                                                                  PCH-5N.F.F                                                                            4.0%                                                                  CCZU-2-F                                                                              6.0%                                                                  CCZU-3-F                                                                              12.0%                                                                 CCZU-5-F                                                                              2.0%                                                                  CC-5-V  16.0%                                                                 PCH-3   7.0%                                                                  BCH-2F.F                                                                              3.0%                                                                  BCH-3F.F                                                                              3.0%                                                                  BCH-5F.F                                                                              3.0%                                                                  BCH-32  2.0%                                                           ______________________________________                                    

What is claimed is:
 1. An electro-optical liquid-crystal displayhaving arealignment layer for realigning the liquid crystals whose field has asignificant component parallel to the liquid-crystal layer andcontaining a liquid-crystalline medium of positive dielectricanisotropy, wherein the medium comprises:at least one compound of theformula I ##STR35## in which R¹ is H, an alkyl or alkenyl radical having1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN orCF₃ or monosubstituted to perhalo-substituted by halogen, where one ormore CH₂ groups in these radicals are optionally, in each caseindependently of one another, replaced by --O--, --S--, --CO--,--CO--O--, --O--CO-- or --O--CO--O-- in such a way that O atoms are notlinked directly to one another,A¹ and A² are each, independently of oneanother,(a) 1,4-cyclohexenylene radical or trans-1,4-cyclohexyleneradical, in which one or more non-adjacent CH₂ groups are optionallyreplaced by --O-- and/or --S--, (b) 1,4-phenylene radical, in which oneor two CH groups are optionally replaced by N, (c) radical selected fromthe group consisting of 1,4-bicyclo[2.2.2] octylene,piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyland 1,2,3,4-tetrahydronaphthaline-2,6-diyl,where the radicals (a) and(b) are optionally substituted by one ore two fluorine atoms, Z¹ and Z²are each, independently of one another, --CO--O--, --O--CO--, --CH₂ O--,--OCH₂ --, --CH₂ CH₂ --, --CH═CH--, --C.tbd.C--, or a single bond, orone of the radicals Z¹ and Z² is --(CH₂)₄ -- or --CH═CH--CH₂ CH₂ --, andm is 0, 1 or 2, and at least one compound of the formula I*a ##STR36##in which z is 1-12, andR* is H, CH₃, C₂ H₅ or n-C₃ H₇.
 2. Aliquid-crystal display according to claim 1, wherein the medium furthercomprises at least one compound of the formula I*c: ##STR37## in whichR* is H, CH₃, C₂ H₅ or n-C₃ H₇,R² * is F, an alkyl or alkoxy radicalhaving 1 to 6 carbon atoms which is unsubstituted ormonosubstituted toperfluorosubstituted by fluorine, and L¹ and L² are each, independentlyof one another, H or F.
 3. A liquid-crystal display according to claim1, wherein the medium further comprises at least one compound of theformula II ##STR38## in which L¹ and L² are each, independently of oneanother, H or F,R² is as defined for R¹, A³ and A⁴ are each,independently, as defined for A¹ and A², Z³ and Z⁴ are each,independently, as defined for Z¹ and Z², and n is 0, 1 or
 2. 4. Aliquid-crystal display according to claim 1, wherein the medium furthercomprises at least one compound of the formula III

    R.sup.3 --(A.sup.5 --Z.sup.5).sub.o --A.sup.6 --R.sup.4    III

in which R³ and R⁴ are each, independently, as defined for R¹, A⁵ and A⁶are each, independently, as defined for A¹ and A², and Z⁵ is in eachease, independently of the others, as defined for Z¹ and Z², and o is 1,2 or
 3. 5. A liquid-crystal display according to claim 1, wherein themedium further comprises at least one compound of the formula IV##STR39## in which R⁵ is as defined for R¹,A⁷ and A⁸ are each,independently, as defined for A¹ and A², Z⁷ and Z⁸ are each,independently, as defined for Z¹ and Z², L¹ and L² are each,independently of one another, H or F, Q is a polyfluoroalkylene radicalof the formula

    --(O).sub.q --(CH.sub.2).sub.r --(CF.sub.2).sub.s --

in whichq is 0 or 1 r is an integer from 1 to 6 and s is an integer from1 to 6, X is H, F or Cl, and p is 0, 1 or
 2. 6. A liquid-crystal displayaccording to claim 1, wherein the medium further comprises at least onecompound of the formula IIa1 ##STR40## in which z is 1-12.
 7. A displayaccording to claim 1, having pixels addressed by means of an activematrix.
 8. A liquid-crystalline medium of positive dielectric anisotropywhich comprises at least one compound of the formula I ##STR41## inwhich R¹ is H, an alkyl or alkenyl radical having 1 to 15 carbon atomswhich is unsubstituted, monosubstituted by CN or CF₃ or monosubstitutedto perhalo-substituted by halogen, where one or more CH₂ groups in theseradicals are optionally, in each case, --O--, --S--, --CO--, --CO--O--,--O--CO-- or --O--CO--O-- in such a way that O atoms are not linkeddirectly to one another,A¹ and A² are each, independently of oneanother, a(a) 1,4-cyclohexenylene radical or trans-1,4-cyclohexyleneradical, in which one or more non-adjacent CH₂ groups are optionallyreplaced by --O-- and/or --S--, (b) 1,4-phenylene radical, in which oneor two CH groups are optionally replaced by N, (c) radical selected fromthe group consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and1,2,3,4-tetrahydronaphthaline-2,6-diyl,where the radicals (a) and (b)are optionally substituted by one or two fluorine atoms, Z¹ and Z² areeach, independently of one another, --CO--O--, --O--CO--, --CH₂ O--,--OCH₂ --, --CH₂ CH₂ --, --CH═CH--, --C.tbd.C--, or a single bond, orone of the radicals Z¹ and Z² is --(CH₂)₄ -- or --CH═CH--CH₂ CH₂ --, andm is 0, 1 or 2,and at least one compound of the formula I* ##STR42## inwhich R¹ * is iE-alkenyl or 3E-alkenyl having 2-7 carbon atoms, R^(2*)is F, an alkyl or alkoxy radical having 1 to 6 carbon atoms which isunsubstituted or monosubstituted to perfluorosubstituted by fluorine,##STR43## l is 0 or 1, and L¹ and L² are each, independently of oneanother, H or F.
 9. A liquid-crystalline medium according to claim 8,which comprisesfrom 10 to 60% by weight of at least one compound of theformula I, and from 5 to 40% by weight, of at least one compound of theformula I*.
 10. A liquid-crystalline medium according to claim 9, whichcomprises:from 10 to 60% by weight, of at least one compound of theformula I, from 5 to 40% by weight, of at least one compound of theformula I*, from 0 to 40% by weight, of at least one compound of theformula II ##STR44## in which L¹ and L² are each, independently of oneanother, H or F,R² is as defined for R¹, A³ and A⁴ are each,independently, as defined for A¹ and A², Z³ and Z⁴ are each,independently, as defined for Z¹ and Z², and n is 0, 1 or 2, from 0 to30% by weight, of at least one compound of the formula III

    R.sup.3 --(A.sup.5 --Z.sup.5).sub.o --A.sup.6 --R.sup.4    III

in whichR³ and R⁴ are each, independently of one another, as defined forR¹, A⁵ and A⁶ are each, independently, as defined for A¹ and A², Z⁵ isin each case, independently of the others, as defined for Z¹ and Z², ando is 1, 2 or 3; from 5 to 50% by weight of at least one compound of theformula IV, ##STR45## in which R⁵ is as defined for R¹,A⁷ and A⁸ areeach, independently, as defined for A¹ and A², Z⁷ and Z⁸ are each,independently, as defined for Z¹ and Z², L¹ and L² are each,independently of one another, H or F, Q is a polyfluoroalkylene radicalof the formula

    --(O).sub.q --(CH.sub.2).sub.r --(CF.sub.2).sub.s --

in whichq is 0 or 1 r is an integer from 1 to 6 and s is an integer from1 to 6, X is H, F or Cl, and p is 0, 1 or
 2. 11. A liquid-crystallinemedium according to claim 10, which comprises:from 30 to 60% by weight,of at least one compound of formula I, from 10 to 25% by weight, of atleast one compound of formula I*, from 0 to 25% by weight, of at leastone compound of formula II, and from 0 to 15% by weight, of at least onecompound of formula III, and from 10 to 30% by weight, of at least onecompound of formula IV.
 12. A liquid-crystalline medium according toclaim 10, which comprisesat least one compound selected from those ofthe formulae Ia or 1b ##STR46## at least one compound selected fromthose of the formulae 1*a to I*f ##STR47## wherein z is 1-12,R* is H,CH₃, C₂ H₅ or n-C₃ H₇, and L¹ and L² are each, independently of oneanother, H or F, optionally, at least one compound selected from thoseof the formulae IIa, IIb, IIc, and/or IId, ##STR48## optionally, atleast one compound selected from those of the formulae IIIa, IIIb andIIIc, ##STR49## and, at least one compound selected from those of theformulae IVa and IVb, ##STR50## in which ##STR51## where R¹, R², R³, R⁴,R⁵, L¹ and L² are each as defined.